I have a Geko 201 with a serial connection to a RCAP2. I want to split the serial connection into two. One going to the RCAP, and the other to a modem on the audio channel of my video TX. This will feed GPS data down to my ground station to be displayed on Google Earth.
What type of decoupling between the RCAP and the Modem do I need to add to do this?

Kilrah,
totally agree. I have several 7.4V LiPo's. I think I am going stick with them and add a DC-DC boosting regulator to bring it up to 12v for the Video. Everything else will run off 6v with 3v for the GPS. I use the Easy star either with 1 x 3000mah or 2s x 2100mah packs. I can divide these two packs and use one for video. Anyone have any do's and don'ts when using DC-DC regulators with LiPo's?

Thomas,
the plane that I am going to use is not electric powered, however I do have an eclectic plane that I would like to use just the video TX and Camera with that runs on 7.4v LiPo's. I had intended on using the same LiPo's to run all my gear when they are in my gas powered plane. I am starting to think that I should just but another 11.1v LiPo to run the video and use Vregs step down to the voltages I need for the rest. That is my main question, should I power everything from one 7.4v battery and step up to 12v for the TX or run the video off a 11.1v LiPo and use a second power source for the GPS and RCAP for safety?

As a frequent lurker of this forum I find I can usually find the answers to my questions without asking them, but I finally have one to ask.
I have just put together my first “proper” UAV / FPV setup. I have ground tested all the components separately and they all work well. I am intending on putting all of the equipment into a trainer I have kicking around. The TX and Camera will be mounted wing with the Nav equipment in a similar place on the opposite wing.
My question is around power for all the various voltages required.
Equipment list.
1w 2.4GHz Lawnmate TX (12v)
420 line Board Camera (12v)
Gecko 201 (3v)
RCAP2 (6v- 12v?)
FMA Copilot FS8 (standard RX 4.8v-6v)
I intend on adding.
GPS Overlay Board
Video source switch
Digital still camera
RS232 Modem on the Audio channel sending NMEA string back to the ground station.
This is probably going to be in a bigger airframe.
I already have 7.4v LiPo’s that I use in my son’s Easystar, I had intended on using them with a DC-DC boosting regulator to give me the needed 12v for the Video system. (Shown here in MR-RC Cam’s project http://www.rc-cam.com/dc-dc.htm ) This would also allow me to also just use the video system to the Easystar if I needed to.
I want to keep the power source for the Video (given that it is the highest current draw) isolated from the RCAP and receiver. I also intend on running my Gecko from an external power source, (See this thread http://www.rcgroups.com/forums/showthread....light=gecko+201 ) for which I will also need 3v regulator. I think for simplicity I will attach this vreg to the RCAP for ease of feeding the Gecko from the same connector as the RS232.
I am currently leaning towards buying a 11.1V LiPo and use it to power the Video without a regulator. (This is within tolerance as far as am aware) And using a 7.4V LiPo with a 3V vreg for the RCAP and the Geko.
Does anyone have any advise on this?

Mac,
Everything I have ever seen about operating temperature of LiPo's state 32f to 140f as a discharging temp. (usually a little cooler max for charging) The easy star is a good insulator which is more often than not an issue for cooling as the discharging packs keep the electronics bay warm. I would try it above 32f and see how much warmer it is inside once you land, that way you can figure out a realistic minimum. Not too much less than freezing though. (If only for the sake of your fingers )

I know this is hard to test if you are only seeing a small glitch (amplified) on the pan servo, but are you sure that its not interference from the motor and it happens with no video TX switched on?
Separation is the best fix, but certain Rx's are much better. Airtronics have a good noise rejection I know. You can use a Notch filter and preamp on the TX if its a real issue though.